Plastics

Thermoplastics are linear chain molecules, sometimes with side bonding of the molecules, but with weak, secondary bonding between the chains.

Explain the effect of load on a thermoplastic, with reference to orientation of chains

Deformation occurs in two ways: elastic in which initially coiled chains are stretched and plastic at higher loads, where secondary bonds weaken and allow the molecular chains to slide over each other. Creep and flow are important. No quantitative details required

Explain the reversible effect of temperature on a thermoplastic, with reference to orientation of chains